Elevator safety brake



p i 14, 1953 N. DI BARTOLOMEO ELEVATOR SAFETY BRAKE 2 SHEETS-SHEET 1 Filed June 29, 1951 April 5 N. DI BARTOLOMEO ELEVATOR SAFETY BRAKE Filed June 29, 1951 2 SHEETS-SHEET 2 Patented Apr. 14, 1953 UNITED STATES PATENT OFFIE 7 Claims.

This invention relates to brake mechanism for stopping the descent of an elevator in case of breakage of its supporting cables. When such a brake operates it is likely to stop the elevator between floors so that the occupants cannot easily escape therefrom.

One object of the present invention, therefore, is to provide means actuable from within the elevator car to momentarily and repeatedly release the brake thereby allowing the car to lower slowly until it is sufficiently near to a floor level to permit opening of the car door and the escape of occupants safely from the car.

A further object is to improve the brake mechanism itself for easy and powerful brake action.

For a complete understanding of this invention, reference may be had to the accompanying drawings in which:

Figure 1 is a somewhat diagrammatic elevational view showing an elevator provided with a safety brake embodying the invention.

Figures 2 and 3 are sectional views through the brake-releasing switch box showing the switch in one of its open and in an intermediate closed position, respectively.

Figure 4 is a horizontal sectional view to a larger scale on line 44 of Figure 1.

Figure 5 is a vertical sectional view on line 55 of Figure 4.

Figures 6 and '7 are detail sectional views on lines 6-6 and 1'l, respectively, of Figure 5 and showing the brake released.

Figure 8 is a View similar to a portion of Figure 7 but showing the brake applied.

Figure 9 is a sectional view on line 9-9 of Figure 4.

Figure 10 is an outer end elevation of the parts shown in Figure 4.

Figure 11 is a view similar to Figure 6, but showing a modification.

Referring first to Figure 1, at I is indicated an elevator well having fixed vertically therein a plurality of guide rails 2 for slidably supporting an elevator car 3. This car 3 is suspended as by one or more cables 4 which pass about one or more pulleys 5 adjacent to the top of the well and pass to a suitable windin drum 6 carried by a shaft 1. Suitable controls actuated by the operator of the elevator car are provided as is well understood in the art for rotatingthe shaft 1 whereby to wind or unwind the cables 4 to cause raising or lowering of the elevator car within the well. Such control mechanism is indicated diagrammatically at It in Figure 1.

The brake mechanism of this invention may be made to cooperate with any one or more of the rails 2. Such a mechanism is shown at l2 applied to the lower wall of the car and having brake shoes engageable with the adjacent rail 2. While only one such mechanism is shown, it will be apparent that as many as may be desired, depending upon the number of guide rails, size and weight of the car, etc., may be employed.

As shown best in Figures 4 to 9, the casing l2 may have slidably guided therein a brake applying and releasing slide I5. This slide is normally urged toward brake-applying position by one or more springs 16 seated in socket members I! carried by a block l3 secured in the casing. As shown the springs l6 engage the outer ends of plugs 20 secured as by threading into the rear end of the slide l5. These plugs 20 may be :provided with guide screws 2| threaded into their rear ends and having heads 22 accessible for turning through holes 23 in a cap 24 enclosing a portion of the inner end of the casing. These screws 2! are slidably guided through guide perforations 25 in the block [8 in the outer end wall 26 of the casing and they are accessible, for removal and replacement and for securing the plugs 20 in position, to a screwdriver passed through the corresponding hole 23.

The outer end of the slide I5 is provided with a neck portion 3% which carries at its outer end a brake shoe member 3i positioned to engage with the edge of the cooperating rail 2. The neck portion 30 passes between a pair of brake shoes 32 and 33 which may be pivoted together by the pintle 34 which is inserted through hinge lugs 35 and 36 carried by the brake shoes 32 and 83, and this pintle 34 extends through slots QB in the top and bottom walls 4! and 42 of the casing and it also extends closely through the neck 30 of the central brake shoe 3!. Thus when the central brake shoe is moved outwardly against the end face of the rail 2, the shoes 35 and 32 are moved with it, withdrawing the rear end portions of the shoes 3| and 32 with respect to a pair of guide pins 44 and 35, and permitting springs 46 surrounding a pin 47 mounted in slots 48 in spaced casingjaws 49 to press the outer ends of the brake shoes 3! and 32 against opposite sides of the rail 2 as shown in Figure 8. Thus on outward motion of the slide :5, the central brake shoe is caused to exert pressure against the inner edge of the corresponding rail 2 by the springs 56, and the side jaws 3i and 32 are caused to be pressed against the sides of the rail 2 by the springs 66. On retraction of the slide E5 the motion of the neck 36 causes the side brake shoes to be pressed back between the bars 44 and 45, causing the inner ends of the brake shoes to be rocked outwardly about the pivot 44 and causing the side brake shoes to free the rail 2.

Manual release of the brake shoes against the action of the springs is produced by power, and this may be taken from the electric cable which passes to the controller I0. At a suitable point within the car, as shown in Figure 1 this being at a point on the side of the control box ID, is positioned the brake release mechanism 50. This brake release mechanism, as shown best in Figure 9, comprises a solenoid 5| having a core 52 above which is positioned an armature 53 pivoted at 54 to a pair of spaced supports 55 carried by the casing I2. The outer end of the armature 53 rides within a central groove 56 of an arm 51 secured to a rock shaft 58. This rock shaft 58, as shown best in Figure 5, is secured to an arm 59 riding within a slot 60 in the slide If, the parts being so disposed that on energization of the solenoid 5|, the armature 53 is depressed and the arm 57 is rocked, this rocking the shaft 58 and the arm 59 in a direction such that the lower end of the arm 59 acts on the side of the slot 60 and retracts the slide l5, thus releasing the brake.

The solenoid 5! may be energized momentarily and repeatedly from the control mechanism 56. Thus the brake may be momentarily and repeatedly released and then be reapplied, so that the car may be let down intermittently by small steps. Thus should the car have been stopped between landings, in which position it would be difiicult, if not impossible, for the occupants of the car to escape therefrom, it can be safely lowered until it is sufficiently close to a landing for the car door to be opened, allowing the occupants to escape.

The shaft 52 extends outside of the casing and is normally held in released angular position by a relatively light cable 65 secured to the outer end of an arm 66 fixed to the shaft 58. This cable 65 passes up along with the suspension cables i and is paid out or wound in therewith. On breakage of the cables 4, however, the cable 65 being too light to support the car will also be broken, causing the arm 66 to be released and permitting the springs I6 and 46 to apply the brake.

Energization of the releasing solenoid 5| is produced by actuation of a switch, a suitable form of which is illustrated in Figures 2 and 3. As there shown a tilting switch of the mercury tube type is shown at 10 mounted on a pivot ll within a switch casing 12. The switch terminals 13 and M are out of electrical connection of the body of mercury when the switch is in either of its extreme tilted positions, one of which is shown in Figure 2, these extreme positions being the off position of the switch. In an intermediate horizontal position shown in Figure 3, the terminals 73 and 14 are electrically connected by the mercury 15 so that the switch is on and in this position the releasing solenoid 5i is energized. The control of the switch position is effected by an actuated lever 16, fulcrumed at 11, and having an end portion 18 which rides between two posts I9 carried by the tilting switch. This lever 16 may be rocked from one side to the other by manual engagement with an actuating knob St at its upper end.

Assuming the switch to be in the position shown in Figure 2, should the operator rock the knob 88 to its other extreme position, the tip switch is rocked to its other extreme position, but

in doing so it passes through the intermediate position shown in Figure 3 where it closes the circult to the solenoid 5|. It cannot, however, be held in this intermediate position since actuated lever '16 is not in control during this intermediate portion of its motion, being out of contact with both of the pins 79. Thus the length of time at each actuation that the circuit is closed is out of control of the operator so that he cannot hold the brake released, as he might if it were possible, and thereby lose control of the descent of the car. When, therefore, the brake has been actuated as by breaking of the cables and stops the car intermediate to its landings, it is then only necessary for the elevator operator to rock the lever 8i? back and forth between its two extreme positions, thus causing repeated and momentary releasing actions of the brake mechanism followed by reapplication of the brake, this action being effective to inch the car downwardly under complete control of the operator until it reaches a proper landing position, whereupon the car door may be opened and the occupants allowed to escape.

As shown, a spring-pressed plunger at (Figure 9) may be positioned beneath the arm 51, this aiding in returning this arm to brake-applying position whenever the cable 65 is broken and the solenoid 5i deenergized.

In Figure 11 a modification in the brake-applying mechanism has been illustrated in which the central neck 44: of the central brake shoe acts through a rod til against the rear faces of balls 9i positioned between cam faces 92 on members 93 carried on the inner faces of the outer shoe members 3! and 32, thus forcing these brake shoes outwardly against the action of a curved or C-shaped leaf spring 95, there being such a leaf spring both above and below the neck portion 44a with its corresponding release mechanism.

From the foregoing description of embodiments of this invention it will be evident to those skilled in the art that various further changes and modifications may be made without departing from the spirit or scope of this invention.

I claim:

1. In combination with an elevator well having track members arranged longitudinally thereof, and a car arranged to travel in said well, and having suspension cables, of a brake mechanism carried by said car and adapted to frictionally engage said members, automatically acting means causing said brake to become operative to stop the car on breakage of said cable, and means actuable from the interior of said car for repeatedly and momentarily releasing said brake mechanism to permit gradual controlled descent of said car to a landing should said brake have acted to stop said car between landings, the length of time of such momentary release being out of control of the operator.

2. In combination with an elevator well having track members arranged longitudinally thereof, and a car arranged to travel in said well, and having suspension cables, of a brake mechanism carried by said car and adapted to frictionally engage said members including electrically actuated releasing mechanism, automatically acting means causing said brake to become operative to stop the car on breakage of said cable, and means for momentarily and repeatedly supplying electrical energy to said brake mechanism when said brake is applied to permit gradual controlled descent of such car to a landing should said brake have acted to stop said car between landings, the

length of time of such momentary supply of electrical energy being out of control of the operator.

3. In combination with an elevator well having track members arranged longitudinally thereof, and a, car arranged to travel in said well and having a suspending cable, of a brake mechanism carried by said car and adapted to frictionally engage said members and including electrically actuated brake-releasing mechanism, a switch for controlling electrical energy to release said brake and movable between two spaced oif positions and having an "on position intermediate to said spaced positions, and operator-actuable means actuable to throw said switch from one to the other of said spaced positions and momentarily close said switch at said intermediate position whereby said brake may be repeatedly and momentarily released to permit gradual and controlled descent of said car should said brake have acted to stop said car between landings, said switch being out of control by said operatoractuable means when said switch is closed whereby the operator is unable to hold said switch closed.

4. In combination with an elevator well having track members arranged longitudinally thereof, and a car arranged to travel in said well and having a suspending cable, of a brake mechanism carried by said car and adapted to frictionally engage said members and including electrically actuated brake-releasing mechanism, a switch for controlling electrical energy to release said brake and movable between two spaced off positions and having an on position intermediate to said spaced positions, and operator-actuable means actuable to throw said switch from one to the other of said spaced positions and momentarily close said switch at said intermediate position whereby said brake may be repeatedly and momentarily released to permit gradual and controlled descent of said car should said brake have acted to stop said car between landings, said switch being out of control of said actuable means while passing through said intermediate on position, whereby the operator is unable to hold said switch in on position.

5. In combination with an elevator well having track members arranged longitudinally thereof,

and a car arranged to travel in said well and having a suspending cable, of a brake mechanism carried by said car and adapted to frictionally engage said members and including electrically actuated brake-releasing mechanism, a tip switch for controlling electrical energy to release said brake and movable between two spaced "011 positions and having an on position intermediate to said spaced positions, and operator-actuable means actuable to tip said switch from one to the other of said spaced positions and momentarily close said switch at said intermediate position whereby said brake may be repeatedly and momentarily released to permit gradual and controlled descent of said car should said brake have acted to stop said car between landings, said operator-actuable means being inoperative to hold said switch in said on position, whereby the operator is unable to hold said switch in on position.

6. In combination with an elevator well rail, of a brake adapted to be carried by a car movable through said well, said brake having a pair of spaced friction shoes arranged one on each side of said rail, and a third shoe opposite an end wall of said rail, and means for pressing all of said shoes against said rail and for releasing all of said shoes therefrom.

7. In combination with an elevator well rail, of a brake adapted to be carried by a car movable through said well, said brake having a pair of spaced friction shoes arranged one on each side of said rail, and a third shoe opposite an end wall of said rail, means for moving said third shoe from and toward said rail, and operative connections from said third shoe to each of said pair of shoes for causing substantially simultaneous application or retraction of all of said shoes relative to said rail.

NICO'LA DI BARTOLOMEO.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 974,447 Sundh Nov. 1, 1910 1,134,765 Scott et a1. Apr. 6, 1915 1,443,841 Gulemundson Jan. 30, 1923 

